[Ovmsdev] 2019 / scripting framework

Michael Balzer dexter at expeedo.de
Fri Jan 11 00:38:40 HKT 2019


Works like a charm :)

I've added the autoinit option to the web UI.

Important for all script writers is to keep in mind we now have a global shared context.

That is very useful to share data between scripts, but needs a little bit of discipline to avoid polluting the global context with local variables and
functions. Any "var", "const", "function" etc. placed into the top level of a script file now is added to the global context.

The best approach is to encourage users to use closures by default for all their scripts, i.e.

    (function(){
        … user code …
    })();

The same rule applies to web plugins.

Node style modules also work nicely. A simple test module:

    // Module       : JSON (not compatible with the browser component!)
    // State        : test/demo
    // Install as   : /store/scripts/lib/JSON.js
    // Load         : JSON = require("lib/JSON");
    // Use          : JSON.print(object);

    exports.print = function(obj, ind) {
      var type = typeof obj;
      if (type == "object" && Array.isArray(obj)) type = "array";
      if (!ind) ind = '';

      switch (type) {
        case "string":
          print('"' + obj.replace(/\"/g, '\\\"') + '"');
          break;
        case "array":
          print('[\n');
          for (var i = 0; i < obj.length; i++) {
            print(ind + '  ');
            exports.print(obj[i], ind + '  ');
            if (i != obj.length-1) print(',');
            print('\n');
          }
          print(ind + ']');
          break;
        case "object":
          print('{\n');
          var keys = Object.keys(obj);
          for (var i = 0; i < keys.length; i++) {
            print(ind + '  "' + keys[i] + '": ');
            exports.print(obj[keys[i]], ind + '  ');
            if (i != keys.length-1) print(',');
            print('\n');
          }
          print(ind + '}');
          break;
        default:
          print(obj);
      }

      if (ind == '') print('\n');
    }


Using it:

    JSON = require("lib/JSON");

    print("Global context:\n");
    JSON.print(this);

    (function(){
      var x = { a: 42, b: "a \"foo\" is no 'bar'", c: [1,2,3], d: { sub: true }, e: ["q","w",17, { e1:22, e2:33 }] };
      print("\nLocal object:\n");
      JSON.print(x);
    })();


Execution:

    OVMS# . test.js
    Global context:
    {
      "print": function () { [native code] },
      "assert": function () { [native code] },
      "OvmsMetricValue": function () { [native code] },
      "OvmsMetricFloat": function () { [native code] },
      "OvmsLocationStatus": function () { [native code] },
      "OvmsCommand": function () { [native code] },
      "JSON": {
        "print": function () { [ecmascript code] }
      }
    }

    Local object:
    {
      "a": 42,
      "b": "a \"foo\" is no 'bar'",
      "c": [
        1,
        2,
        3
      ],
      "d": {
        "sub": true
      },
      "e": [
        "q",
        "w",
        17,
        {
          "e1": 22,
          "e2": 33
        }
      ]
    }

Nice :)

Regards,
Michael


Am 10.01.19 um 10:10 schrieb Mark Webb-Johnson:
> I’ve committed my work on a production javascript framework. The changes are quite extensive, and with the one exception of ‘ovmsprint’, should be backwards
> compatible.
>
> The overall goal is to be able to run a javascript code system alongside our standard firmware code. Users could then write javascript, and modify scripts
> already running on the device (without firmware changes). Unlike the previous version (where scripts were loaded, compiled, run, then dumped), this approach
> is designed to keep scripts in memory; this vastly increases the opportunities for what can be done with the system.
>
> Changes made include:
>
>   * Move scripting to be a component
>   * Make DukTape use SPIRAM for as much as possible
>   * Run the javascript engine in it's own task (OVMS DukTape)
>   * Change the way extensions functions are registered
>     (just call RegisterDuktapeFunction, rather than messing around with the internals of Duktape)
>   * Catch compilation and parsing errors (fail gracefully - finally!)
>   * Support 'print' and 'assert' javascript framework
>   * Output (via print) goes to current console, or logged if no console
>   * Autoinit (and run) /store/scripts/ovmsmain.js
>   * Support node.js style modules
>   * Control with config auto javascript (default enable)
>
>
> The main TODO is to provide a facility for reloading the engine (new scripts/modules). At the moment, the module needs to be rebooted (ugly). There is also a
> lot of work still to do on making some actually useful modules. And we also need to work out what to do with events (now that they can be delivered to running
> javascripts).
>
> But, anyway, for the moment:
>
>     I (128) script: Initialising SCRIPTS (1600)
>     I (132) script: Using DUKTAPE javascript engine
>     I (0) script: Duktape: Creating heap
>     I (10) script: Duktape: Initialising module system
>     I (20) script: Duktape: Scripting task is running
>     I (906) script: Duktape: Executing ovmsmain.js
>     I (936) script: Hello world
>
>     OVMS# vfs cat /store/scripts/ovmsmain.js
>     print("Hello world\n”);
>
>     OVMS# test javascript
>     Javascript 1+2=3
>
>
> Regards, Mark.
>
>> On 8 Jan 2019, at 11:00 PM, Michael Balzer <dexter at expeedo.de <mailto:dexter at expeedo.de>> wrote:
>>
>> Mark,
>>
>> welcome back, awesome news on the JS and FCC stuff :)
>>
>> I've got some fixes and some feedback on the web plugins in progress, I'll get that done until the weekend (got some free days left).
>>
>> Regards,
>> Michael
>>
>>
>> Am 08.01.19 um 05:27 schrieb Mark Webb-Johnson:
>>> Firstly, a very belated merry xmas, and happy 2019 to everyone. I hope that you all got to spend good times with friends and family, as I did. I’ve been
>>> travelling, and just got back home to a very large eMail inbox.
>>>
>>> During my travels, I did manage to re-work the javascript framework to be single task based. That seems to work well, and now I’m back I will test on my
>>> car. The new framework is backwards compatible - apart from memory usage (one more task with a stack), it has no impact to the flow. It will, however, allow
>>> us to extend this a lot more and become much more useful. Assuming no issues, I will be able to commit that soon.
>>>
>>> As we are up to 144 commits since 3.1.011, perhaps it is well past due for 3.1.012? I was hoping that Espressif would have fixed the bug related to wear
>>> levelling version upgrades that Michael helped to identify, but not yet. Any objections to a 3.1.012 release to EAP at the end of this week?
>>>
>>> The CE/FCC certification work is progressing. No issues so far. I’ll let you know as soon as we get near completion for this.
>>>
>>> I’m working through my inbox now, and will reply individually to questions there.
>>>
>>> Regards, Mark.
>>>
>>> _______________________________________________
>>> OvmsDev mailing list
>>> OvmsDev at lists.openvehicles.com <mailto:OvmsDev at lists.openvehicles.com>
>>> http://lists.openvehicles.com/mailman/listinfo/ovmsdev
>>
>> -- 
>> Michael Balzer * Helkenberger Weg 9 * D-58256 Ennepetal
>> Fon 02333 / 833 5735 * Handy 0176 / 206 989 26
>>
>>
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>
>
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-- 
Michael Balzer * Helkenberger Weg 9 * D-58256 Ennepetal
Fon 02333 / 833 5735 * Handy 0176 / 206 989 26

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